1. Field of the Disclosure
The disclosure relates to a light emitting device and a method of fabricating the light emitting device.
2. Description of Related Art
Light emitting diodes (LEDs) may have horizontal structures and vertical structures, etc. in application. Since electrodes of the conventional horizontal LED are disposed at the same side thereof, a mesa portion may have a current crowding phenomenon, which may cause a poor heat dissipation effect and limit a magnitude of a driving current that can be afforded by the LED. Therefore, a present high power LED applies the vertical structure.
FIG. 1 illustrates a cross-sectional view of a conventional LED. Referring to FIG. 1, the LED 100 is a vertical LED, which includes electrodes 110 and 120, a first semiconductor layer 130, a second semiconductor layer 140, and an active layer 150. In the LED 100, along with different distances between the electrodes 110 and 120, distribution densities of a current I are also different, and at a region (for example, right below the electrode 110) with higher distribution density of the current I, the active layer 150 may have higher lighting efficiency. However, since a position of the electrode 110 is just located above the region with the highest light emitting efficiency, the electrode 110 may block the light L emitted from the active layer 150, so that a total light emitting efficiency of the LED 100 is influenced.
Moreover, when the vertical LED 100 is fabricated, an epitaxy structure Ep formed by the first semiconductor layer 130, the second semiconductor layer 140 and the active layer 150 is generally formed on a growth substrate (not shown), then the epitaxy structure Ep is transferred to a carrier substrate (not shown), and the growth substrate (not shown) is subsequently removed. Presently, a method of separating the growth substrate is mainly a laser lift-off (LLO) method, by which a KrF laser located at a side of the growth substrate is used to irradiate an interface between the growth substrate and the semiconductor layer (for example, a gallium nitride layer), and after the device interface absorbs enough energy, the growth substrate is separated therefrom. However, when the LLO method is used, control of the laser energy is not easy, and fissures are liable to be generated around the device within a width range of about 10 μm, and after a long time operation of the device, a problem of current leakage is occurred. Therefore, the LED 100 usually has a current leakage phenomenon, especially at a sidewall part thereof.